U.S. patent application number 09/915958 was filed with the patent office on 2002-03-21 for diorganopolysiloxane/acrylate ester copolymer emulsion composition for fabric treatment.
Invention is credited to Naganawa, Tsutomu, Ona, Isao.
Application Number | 20020035186 09/915958 |
Document ID | / |
Family ID | 27805882 |
Filed Date | 2002-03-21 |
United States Patent
Application |
20020035186 |
Kind Code |
A1 |
Ona, Isao ; et al. |
March 21, 2002 |
Diorganopolysiloxane/acrylate ester copolymer emulsion composition
for fabric treatment
Abstract
A diorganopolysiloxane/acrylate ester copolymer containing
emulsion composition for fabric treatment cures at room temperature
through removal of water with formation of flexible and highly
flame retardant coatings that do not crack even at very low
temperatures. Highly flame retardant fabrics can be provided by
treatment with the emulsion composition. The emulsion composition
contains (A) an emulsion of a copolymer of (a-1) an hydroxyl
endblocked diorganopolysiloxane having at least two silicon bonded
alkenyl groups in each molecule, and (a-2) an acrylate ester
monomer; (B) colloidal silica; (C) a condensation catalyst, and (D)
an inorganic flame retardant.
Inventors: |
Ona, Isao; (Chiba
Prefecture, JP) ; Naganawa, Tsutomu; (Chiba
Prefecture, JP) |
Correspondence
Address: |
Dow Corning Corporation
Intellectual Property Department
Mail CO1232
P. O. Box 994
Midland
MI
48686-0994
US
|
Family ID: |
27805882 |
Appl. No.: |
09/915958 |
Filed: |
July 26, 2001 |
Current U.S.
Class: |
524/409 ;
524/492; 524/493 |
Current CPC
Class: |
D06M 11/45 20130101;
D06M 13/148 20130101; D06M 11/69 20130101; D06M 11/47 20130101;
D06N 3/0063 20130101; D06N 3/042 20130101; D06N 3/128 20130101;
D06M 13/085 20130101; D06M 13/11 20130101; C08G 77/442 20130101;
D06M 13/156 20130101; C09D 183/10 20130101; D06M 15/263 20130101;
D06M 15/643 20130101; C09K 21/00 20130101; D06M 13/08 20130101;
D06M 13/292 20130101; D06M 11/79 20130101; D06M 15/3568
20130101 |
Class at
Publication: |
524/409 ;
524/492; 524/493 |
International
Class: |
C08K 003/10; C08K
003/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2000 |
JP |
JP 2000-232245 |
Claims
1. A diorganopolysiloxane/acrylate ester copolymer containing
emulsion composition for fabric treatment comprising (A) 100 weight
parts of an emulsion containing a copolymer formed from (i) an
hydroxyl endblocked diorganopolysiloxane having a least two silicon
bonded alkenyl groups in each molecule and (ii) an acrylate ester
monomer; (B) 1-100 weight parts of colloidal silica; (C) 0.01-15.0
weight parts of a condensation catalyst; and (D) 1-50 weight parts
of an inorganic flame retardant.
2. A composition according to claim 1 wherein condensation catalyst
(C) is a metal salt of an organic acid selected from the group
consisting of dibutyltin dilaurate, dibutyltin diacetate,
dibutyltin dioctate, tin laurate, and zinc octanoate; a titanate
ester selected from the group consisting of tetrabutyl titanate,
tetrapropyl titanate, and dibutoxy titanium bis(ethyl
acetoacetate); or an amine compound selected from the group
consisting of n-hexylamine and guanidine.
3. A composition according to claim 1 wherein inorganic flame
retardant (D) is aluminum hydroxide, antimony oxide,
chlorophosphonate, or bromophosphonate.
4. A composition according to claim 3 further comprising (E) 0.1-30
weight parts of an organic flame retardant selected from the group
consisting of halogenated hydrocarbons, organophosphates, or
silicones.
5. A method of treating fabrics comprising applying to fabrics the
composition according to claim 1.
6. A method according to claim 5 in which the composition is
applied to the fabrics as a fabric dip.
7. A method according to claim 6 in which the fabric is a material
used in manufacturing tents or automotive air bags.
8. A fabric treated in accordance with the method defined in claim
5.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
[0003] Not applicable.
[0004] 1. Field of the Invention
[0005] This invention relates to a diorganopolysiloxane/acrylate
ester copolymer emulsion composition for treatment of fabrics. It
also relates to fabrics treated with the emulsion composition. In
particular, the diorganopolysiloxane/acrylate ester copolymer
emulsion composition for fabric treatment cures at room temperature
through removal of water, forming a flexible and highly flame
retardant coating. The invention further relates to such highly
flame retardant fabrics treated with the emulsion composition.
[0006] 2. Background of the Invention
[0007] Acrylate ester polymers have been used as coatings for
fabrics used for tents, rainwear, and ski wear due to their
excellent film forming performance, weather resistance, oil
resistance, and waterproofness, i.e., hydrostatic resistance.
However, acrylate ester polymers have a low moisture permeability
and a low water repellency, which has negative consequences for
their application as coatings for raincoats or ski wear. Thus, the
low moisture permeability results in the interior build up of water
vapor, while the low water repellency necessitates the use of a
water repellent. In addition, fabric coatings of acrylate ester
polymer are subject to cracking during flexure at very low
temperatures of -30.degree. C. or -40.degree. C.
[0008] Diorganopolysiloxane/acrylate ester copolymer emulsion
compositions have been used as coating agents, as in British Patent
1161072 (Aug. 3, 1969), Japanese Patent Publication(Kokoku) No. Sho
54-5007 (5,007/1979), and Japanese Patent Application
Publication(Kokai) No. Hei 1-168972 (168,972/1989). However, these
compositions do not have satisfactory film strength at very low
temperatures, and are not able to resist cracking at very low
temperatures.
[0009] A diorganopolysiloxane/acrylate ester copolymer emulsion
composition containing colloidal silica has been described Japanese
Patent Application Publication(Kokai) No. Hei 5-287217
(287,217/1993). This emulsion composition has a low flame
retardancy, and so it has not been used as a coating agent where
flame retardancy is required, such as in automotive airbags or
prefabricated tents. In addition, the emulsion is unable to provide
an adequate flame retardancy when used as a binder for attachment
of photocatalytic titanium oxide.
BRIEF SUMMARY OF THE INVENTION
[0010] Therefore, it is an object of this invention is to provide a
diorganopolysiloxane/acrylate ester copolymer emulsion composition
for fabric treatment that cures at room temperature through removal
of water to form a flexible, and highly flame-retardant coating
that will not crack, even at very low temperatures. Another object
is to provide highly flame retardant fabrics treated with the
emulsion composition.
[0011] These and other features of the invention will become
apparent from a consideration of the detailed description.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0012] Not applicable.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The diorganopolysiloxane/acrylate ester copolymer emulsion
composition for fabric treatment according to the present invention
contains (A) 100 weight parts of an emulsion of a copolymer formed
from (a-1) an hydroxyl endblocked diorganopolysiloxane having at
least two silicon bonded alkenyl groups in each molecule, and (a-2)
an acrylate ester monomer; (B) 1-100 weight parts of colloidal
silica; (C) 0.01-15.0 weight parts of a condensation catalyst; and
(D) 1-50 weight parts of an inorganic flame retardant.
[0014] Diorganopolysiloxane component (a-1) is an hydroxyl
endblocked siloxane that contains at least two silicon bonded
alkenyl groups in each molecule. At least two alkenyl groups are
required for radical copolymerization with component (a-2) to form
strong and flexible coatings. The presence of hydroxyl groups at
both molecular chain terminals is necessary to cause reaction
through condensation with component (B) of a network polymer with a
high degree of polymerization (DP) whose main chain is composed of
only soft segments. The alkenyl group is exemplified by vinyl,
allyl, and hexenyl groups, with vinyl groups being preferred.
Non-alkenyl Si-bonded organic groups present in component (a-1) can
be exemplified by alkyl groups such as methyl, ethyl, butyl, hexyl,
and octyl; aryl groups such as phenyl; and substituted hydrocarbyl
groups such as 3,3,3-trifluoropropyl. Methyl is the preferred
non-alkenyl Si-bonded organic group. While the molecular structure
of the diorganopolysiloxane should be straight chain, it may
include a partially branched structure. Its kinematic viscosity at
25.degree. C. should be 50-1,000,000 mm.sup.2/s, preferably
100-500,000 mm.sup.2/s.
[0015] Diorganopolysiloxanes (a-1) are exemplified by silanol
endblocked methylvinylpolysiloxanes, silanol endblocked
dimethylsiloxane-methylvinyl- siloxane copolymers, silanol
endblocked methylhexenylpolysiloxanes, and silanol endblocked
dimethylsiloxane-methylhexenylsiloxane copolymers. They can be
synthesized by (i) ring opening polymerization of cyclic
diorganopolysiloxanes, (ii) hydrolysis and condensation of straight
chain or branched diorganopolysiloxanes functionalized with
hydrolyzable groups such as alkoxy or acyloxy groups, or (iii)
hydrolysis of one or more diorganodihalosilanes.
[0016] Acrylate ester monomer component (a-2) is exemplified by
monomers such as methyl acrylate, ethyl acrylate, butyl acrylate,
octyl acrylate, methyl methacrylate, ethyl methacrylate, propyl
methacrylate, butyl methacrylate, octyl methacrylate, 2-ethylhexyl
methacrylate, and hydroxyethyl methacrylate. Component (a-2) should
contain such monomers as its main constituent, but small amounts of
other constituents may be included such as acrylic acid,
methacrylic acid, acrylamide, acrylonitrile, vinyl chloride,
styrene, .alpha.-methylstyrene, vinyl acetate,
vinyltrialkoxysilanes, vinyltriacetoxysilane, or
.gamma.-methacryloxypropyltrimethoxysilane.
[0017] Emulsion component (A) can be prepared by first adding water
(c) and emulsifying agent (b) to component (a-1) and preparing a
diorganopolysiloxane emulsion; adding component (a-2) to the
emulsion; and copolymerizing (a-1) and (a-2) in the presence of a
radical polymerization initiator.
[0018] Emulsifying agent (b) functions to emulsify
diorganopolysiloxane (a-1), and it can be an anionic or nonionic
emulsifying agent. The anionic emulsifying agent can be the salt of
a higher aliphatic acid, the salt of the sulfate ester of a higher
alcohol, the salt of an alkylbenzene sulfonic acid, the salt of an
alkylnaphthalene sulfonic acid, an alkylphosphonate, or the salt of
the sulfate ester of a polyethylene glycol. The nonionic surfactant
can be a polyoxyethylene alkylphenyl ether, an aliphatic acid ester
of sorbitan, an aliphatic acid ester of polyoxyethylene sorbitan,
the aliphatic acid ester of a polyoxyalkylene, or an aliphatic acid
monoglyceride. The surfactant can be a single surfactant or a
mixture of two or more surfactants.
[0019] Emulsifying agent (b) can be used in the amount of 1-50
weight parts per 100 weight parts of component (a-1), preferably
2-30 weight parts per 100 weight parts of component (a-1). Water
(c) should be in sufficient quantity to enable preparation of an
aqueous emulsion composition by emulsification of components
(A)-(D). Water (c) can be present in the amount of 50-1,000 weight
parts per 100 weight parts of component (a-1), preferably 100-500
weight parts per 100 weight parts of component (a-1). Acrylate
ester monomer (a-2) should be used in the amount of 1-100 weight
parts, preferably 5-50 weight parts, per 100 weight parts of the
emulsion of components (a-1), (b), and (c). Radical polymerization
initiators used for copolymerization can be exemplified by ammonium
persulfate, potassium persulfate, hydrogen peroxide,
azobisisobutyronitrile, dibutyl peroxide, and benzoyl peroxide.
[0020] Copolymer emulsions (A) can be prepared by the following
method. First, in a homogenizer, octamethylcyclotetrasiloxane, and
methyl and vinyl functional cyclic diorganosiloxanes, are
emulsified using an anionic emulsifying agent such as
dodecylbenzene sulfonic acid. Ring opening polymerization is
carried out with heating to 70-90.degree. C. Polymerization is
continued at lower temperatures of 10-40.degree. C. to synthesize
an emulsion of hydroxyl endblocked diorganopolysiloxane bearing
pendant vinyl groups, i.e., component (a-1). This emulsion is
heated to 80-85.degree. C., radical polymerization initiator is
added dropwise, the acrylate ester monomer (a-2) is added while
stirring, and the polymerization reaction is allowed to continue
for 5-8 hours. The product of this process is emulsion (A)
containing the copolymer.
[0021] Colloidal silica (B) is the reinforcing crosslinker which
strengthens the coating. It can be a material such as fumed
colloidal silica, precipitated colloidal silica, or colloidal
silica with a particle size of 0.0001-0.1 .mu.m that has been
stabilized by sodium or ammonium or aluminum. Component (B) should
be used in the amount of 1-100 weight parts, preferably 2-50 weight
parts, more preferably 5-30 weight parts, in each case, per 100
weight parts of emulsion (A).
[0022] Condensation catalyst (C) accelerates the condensation
reaction between colloidal silica (B) and emulsion (A). Component
(C) can be the metal salt of an organic acid such as dibutyltin
dilaurate, dibutyltin diacetate, dibutyltin dioctate, tin laurate,
and zinc octanoate; a titanate ester, such as tetrabutyl titanate,
tetrapropyl titanate, and dibutoxy titanium bis(ethyl
acetoacetate); or an amine compound such as n-hexylamine and
guanidine, including hydrochlorides thereof. In preferred
embodiments, the condensation catalyst is prepared in the form of
an emulsion using an emulsifying agent and water. Component (C) can
be used in the amount of 0.01-15.0 weight parts, preferably
0.05-10.0 weight parts, in each case per 100 weight parts of
emulsion (A).
[0023] Inorganic flame retardant (D) is an essential component, and
it is the component responsible for imparting flame retardancy to
the emulsion composition. Component (D) is essential because base
fabrics for prefabricated tent materials and automotive airbags are
made of very flammable nylon and polyester fibers. In addition,
base fabrics for photo catalytic titanium oxide loaded deodorizing
curtains consist primarily of polyester substrates. Inorganic flame
retardant (D) is exemplified by metal compounds such as antimony
oxide, aluminum hydroxide, and chloroplatinic acid; and by
phosphorus compounds such as chlorophosphonate and
bromophosphonate. A single flame retardant or mixture of two or
more flame retardants may be used. Antimony oxide and aluminum
hydroxide are most preferred. Component (D) can be used in the
amount of 1-50 weight parts, preferably 3-30 weight parts, in each
case per 100 weight parts of emulsion (A). Flame retardancy will be
inadequate at less than 1 weight part, while exceeding 50 weight
parts of (D) not only reduces coating adherence to fabrics, but
reduces strength of the coating. Flame retardant (D) can be used as
a dispersion in water, or when it is intended to be knife coated on
fabric, used as a paste by addition of small amounts of a
thickener. When the viscosity becomes high, uniform dispersions can
be prepared by mixing the micro-particulate flame retardant with a
mixing device.
[0024] The emulsion composition can also contain organic flame
retardants (E) in addition to inorganic flame retardant (D).
Suitable organic flame retardants (E) include halogenated
hydrocarbons such as hexabromocyclododecane, chlorinated paraffins,
chlorinated polyphenyls, and tetrabromobisphenol A;
organophosphates such as diphenyl octyl phosphate and tributyl
phosphate; and silicone flame retardants such as silicone resins
and silicone powders. Component (E) can be used in the amount of
0-50 weight parts, preferably 0.1-30 weight parts, in each case per
100 weight parts of emulsion (A).
[0025] Emulsification of the various components (A)-(E) is followed
by adjustment of the pH to 9-12 and ageing, to promote thorough
crosslinking of the components in the emulsion and enable formation
of a solid, strong coating, simply by removal of the water
component. The pH adjusting agent can be an organic amine such as
dimethylamine, ethylenediamine, monoethanolamine, triethanolamine,
morpholine, and 2-amino-2-methyl-1-propanol; or an alkali metal
hydroxide such as sodium hydroxide and potassium hydroxide. Organic
amines are preferred. The pH adjustment, as noted, is followed by
ageing for a prescribed period of time and at a prescribed
temperature. Ageing should be carried out at temperatures that will
not break the emulsion. The ageing temperature is typically
10-70.degree. C., preferably 20-50.degree. C. Ageing time should be
established to correspond to ageing temperature, i.e., at least one
week is preferred at 25.degree. C., whereas at least four days is
preferred at 40.degree. C. The pH of the emulsion can be less than
9 when there is no requirement for room temperature storage
stability.
[0026] Diorganopolysiloxane/acrylate ester copolymer emulsion
compositions containing components (A)-(D) and (A)-(E) may contain
suitable amounts of other components, including thickeners such as
carboxymethylcellulose, methylcellulose, hydroxyethylcellulose,
polyvinyl alcohol, polyacrylic acid or salt thereof; calcium
carbonate; fillers; pigments; dyes; heat stabilizers;
preservatives; and impregnants such as aqueous ammonia.
[0027] The diorganopolysiloxane/acrylate ester copolymer emulsion
composition of the invention has an excellent room temperature
storage stability, and it readily cures at room temperature through
removal of the water fraction, to form a highly flame retardant
coating that strongly adheres to fabrics. The resulting coatings
exhibit excellent flexibility even at low temperatures such as
-20.degree. C. Consequently, the composition is useful as a
treating agent for fabrics used in the manufacture of tents, rain
wear, ski wear, and automotive airbags. It is also useful as a
binder for application of photo catalytic titanium oxide to
curtains.
[0028] For purposes of the invention, the term fabric is intended
to include weaves; knits; non-wovens; and papers made of natural,
synthetic, semi-synthetic, regenerated, and inorganic fibers.
Natural fibers are exemplified by hair, wool, silk, hemp, flax,
cotton, angora, mohair, and asbestos. Synthetic fiber are
exemplified by nylon, polyester, polyamide, polyacrylonitrile,
polyvinyl chloride, vinylon, polyethylene, polypropylene, and
spandex. Semi-synthetic fibers are exemplified by acetate.
Regenerated fibers are exemplified by rayon and bemberg. Inorganic
fibers are exemplified by glass fiber, carbon fiber, and silicon
carbide fiber.
EXAMPLES
[0029] The invention is explained in greater detail by the
following working examples. Parts in these examples denotes weight
parts and % denotes weight percent. Viscosity values were measured
at 25.degree. C. Properties of the cured coatings and treated
fabrics were evaluated using the following procedures.
[0030] Coating Properties
[0031] Formation of Coating--A sheet formed by the coating was made
by pouring 30 g of the diorganopolysiloxane/acrylate ester
copolymer emulsion composition into an aluminum form which was
15.times.11.times.0.5 cm. It was then placed on a
polytetrafluoroethylene sheet and maintained for three days at room
temperature, i.e., about 25.degree. C.
[0032] Measurement of the Physical Properties of the Coating--A
dumbbell shaped test specimen was prepared from a sheet produced in
(1) above using a 3763-6W dumbbell die. The tensile strength
(kgf/cm.sub.2) and elongation (percent) were measured on this test
specimen at 25.degree. C. and at -20.degree. C., with a pulling
rate of 50 cm/minute using Tensilon Model UTM-1-2500SL instrument
of Toyo Baldwin Kabushiki Kaisha.
[0033] Flexural Properties--Using a Mini subzero Model MC-71
instrument of Tabai Kabushiki Kaisha, a sheet with a size of
4.times.2 cm and a thickness of about 0.8 mm made as in (1) above,
was maintained for two hours at 25.degree. C. or -20.degree. C. One
end of the sheet was then fixed in a pincette. A bending test was
executed by elevating the other end. Evaluations were carried out
using a scale where + indicated that absolutely no changes were
seen even after 30 flexes, .DELTA. indicated that breakage occurred
at about the 10th flex, and .times. indicated that breakage
occurred at the first flex.
[0034] Fabric Properties
[0035] Fabric Coating--The diorganopolysiloxane/acrylate ester
copolymer emulsion composition was coated with an applicator on a
taffeta base fabric of 100 percent polyester used for prefabricated
tents, so as to provide a film thickness of 30 .mu.m. This was
followed by drying the fabric for two days at room temperature, and
then heat treating it for three minutes at 130.degree. C.
[0036] Hydrostatic Resistance and Water Repellency of the
Fabric--The hydrostatic resistance in mm, and the water repellency,
were measured respectively, according to Section 5.1 Water
Resistance Method A, and Section 5.2 Water Repellency by Spray
Testing, of the Japanese Industrial Standard (JIS) L 1092
methodology, entitled Test Methods for the Water Resistance of
Fabrics.
[0037] Fabric Flame Retardancy--The oxygen index was measured by
conducting the combustion test specified in Japanese Industrial
Standard (JIS) K 7201, entitled Combustion Test Methods for
Plastics using the Oxygen Index Method.
[0038] Adhesion by the Coating to the Fabric--The coating formed on
the base fabric was strongly rubbed with a finger, and the
adherence was evaluated by visual inspection using the three level
scale noted below. Generally, low adherence will result in
introduction of cracks in the coating followed by peeling and
debonding from the base fabric. According to the three level scale,
+ indicated that cracking and debonding of the coating were not
seen, and that the coating was strongly adhered; .DELTA. indicated
that some cracking appeared in the coating, and that some
separation of the coating from the base fabric was seen; and
.times. indicated that the coating debonded from the base
fabric.
[0039] Coating Tackiness--The presence or absence of tackiness in
the coating was evaluated using the scale noted below, based on a
tactile sensation upon application of a fingertip. In the scale, +
indicated that the coating was smooth and dry and that no tackiness
was observed; .DELTA. indicated that a slight tackiness could be
perceived; and .times. indicated that the coating was very
tacky.
Example 1
[0040] Two parts of dodecylbenzene sulfonic acid and 53.64 parts of
water were added to a mixture of 40 parts of a dimethylcyclic
siloxane with a DP of four and 4 parts of a methylvinylcyclic
siloxane with a DP of 4, and the combination was mixed to
homogeneity for 30 minutes with a stirrer. The resulting mixture
was passed twice through an homogenizer emulsifier at a pressure of
350 kg/cm.sup.2 and provided a uniform emulsion. This emulsion was
held for two hours at 85-90.degree. C. and thereafter cooled to
20-30.degree. C. and polymerized for three hours. 0.36 parts of
sodium carbonate was added for neutralization. The product was an
emulsion containing a dimethysiloxane-methylvinylsiloxane
copolymer. It is referred to hereafter as base emulsion A. The
extracted diorganopolysiloxane copolymer was a gum material with
the average molecular formula: 1
[0041] Four parts of methyl methacrylate was added to 90 parts of
base emulsion A, and homogeneously dispersed by stirring for 30
minutes. The dispersion was transferred to a three neck flask, a
previously prepared aqueous solution of 0.2 parts of potassium
persulfate dissolved in 5.8 parts of water was added, and the
reaction system was placed under a nitrogen blanket. The
temperature was raised to 70-80.degree. C. and held for three hours
to carry out the polymerization. The product was an emulsion,
hereafter referred to as emulsion A-1, containing a copolymer of
methyl methacrylate with the dimethylsiloxane-methylvinylsiloxane
copolymer. A drop of emulsion A-1 was placed on a glass plate and
dried. The product was a completely transparent film which
confirmed that the dimethylsiloxane-methylvinylsiloxane copolymer
and methyl methacrylate had undergone homogeneous copolymerization.
To 85.0 parts of emulsion A-1 were added 15 parts of colloidal
silica, 0.2 parts of diethylamine as a pH adjusting agent, and 0.3
parts of a 50 percent emulsion containing dibutyltin dilaurate.
This was followed by dissolution and dispersion to homogeneity.
Ageing for one week at 45.+-.3.degree. C. provided an emulsion A-2
having a pH of 11-12. To 100 parts of emulsion A-2 were added 8
parts of microparticulate aluminum hydroxide and 2 parts of
hexabromocyclododecane. With mixing, this provided an emulsion
composition referred to hereafter as emulsion composition A-3. The
properties of the coating afforded by emulsion composition A-3 were
measured, as well as properties of a polyester taffeta fabric that
had been coated with emulsion composition A-3. The results are
shown in Table 1.
[0042] As the results in Table 1 reveal, the cured coating from the
diorganopolysiloxane/methyl methacrylate copolymer emulsion
composition A-3 provided high values for tensile strength and
elongation, and had a good flexibility at both low, i.e.,
-20.degree. C., and ambient, i.e., 25.degree. C., temperatures.
Moreover, the coating had good adherence to the base fabric, it was
not tacky, and it had an excellent water resistance, i.e.,
hydrostatic resistance and water repellency, and flame retardancy.
The polyester taffeta fabric treated with emulsion composition A-3
was confirmed to be very well suited for application to fabrics
used in prefabricated tent making for very cold environments.
Comparative Example 1
[0043] A diorganopolysiloxane/methyl methacrylate copolymer
emulsion composition was prepared as in Example 1, but without
adding colloidal silica, diethylamine, and the emulsion of
dibutyltin dilaurate used in Example 1. The properties of the
resulting emulsion composition were measured as in Example 1, and
the results are shown in Table 1.
Comparative Example 2
[0044] A diorganopolysiloxane/methyl methacrylate copolymer
emulsion composition was prepared as in Example 1, but without
adding diethylamine and the emulsion of dibutyltin dilaurate used
in Example 1. The properties of the resulting emulsion composition
were measured as in Example 1, and the results are shown in Table
1.
Comparative Example 3
[0045] 45 parts of water, 2.5 parts of the anionic surfactant
sodium dodecylbenzene sulfonate, 1.5 parts of the nonionic
surfactant polyoxyethylene (14.5) octyl phenyl ether, and 2 parts
of sodium persulfate, were introduced into a four neck flask
equipped with a separatory funnel and mixed to homogeneity. A
mixture of 11 parts of methyl methacrylate and 33 parts of ethyl
acrylate was added dropwise to the flask from the separatory
funnel. After the completion of the addition, the reaction was
maintained for 5 hours at 75.degree. C. The product was an emulsion
of methyl methacrylate/ethyl acrylate copolymer. The properties of
the emulsion were measured as in Example 1, and the results are
shown in Table 1.
Comparative Example 4
[0046] The properties of emulsion A-2 prepared in Example 1 were
measured, and the results are shown in Table 1.
1 TABLE 1 Present Invention Comparative Examples Item Example
Comparative Comparative Comparative Comparative Property Measured 1
Example 1 Example 2 Example 3 Example 4 Tensile Strength
(kgf/cm.sup.2) @ 25.degree. C. 43 37 35 .gtoreq.100 45 @
-20.degree. C. 46 52 50 .gtoreq.100 49 Elongation, percent @
25.degree. C. 830 610 590 530 880 @ -20.degree. C. 810 550 530 2
820 Flexibility @ 25.degree. C. + + + + + @ -20.degree. C. +
.DELTA. .DELTA. x + Hydrostatic Resistance .gtoreq.500 .gtoreq.500
.gtoreq.500 .gtoreq.500 .gtoreq.500 (mm) Water Repellency 80 80 80
50 80 Oxygen Index 18.3 22.1 22.2 23.0 23.5 Adherence to Fabric + +
+ + + Coating Tack + .DELTA. .DELTA. + + Overall Evaluation as Very
Unsuitable Unsuitable Unsuitable Unsuitable due to Tent Fabric in
Very Cold Suitable due to due to due to Unsatisfactory Flame
Environments unsatisfactory unsatisfactory unsatisfactory
Retardancy Cold Cold Cold resistance Resistance Resistance and
unsatisfactory Flame Retardancy
Example 2
[0047] Emulsion composition A-3 prepared in Example 1 was adjusted
to a content of 4 weight percent nonvolatile component and 96
weight percent water fraction, and poured into a rectangular vat.
Polyester taffeta fabric used in the manufacture of prefabricated
tents was immersed for 5 seconds in the bath, wrung out on a mangle
roll at an expression ratio of 50 percent such that there was 2
weight percent add on to the taffeta fabric. It was dried overnight
at room temperature, and heat treated for three minutes at
130.degree. C. The properties of the resulting dip treated
polyester taffeta fabric were measured, and the results are shown
in Table 2. The results shown in Table 2 demonstrate that dip
treatments with emulsion compositions A-3 produce fabric for very
cold weather prefabricated tent material equivalent to fabrics
produced in Example 1.
Comparative Example 5
[0048] Polyester taffeta fabric used for manufacturing
prefabricated tents was dip treated as in Example 2 using emulsions
prepared in Comparative Examples 1-4. Post treatment properties
were measured, and the results are shown in Table 2.
2 TABLE 2 Example 2 Comparative Example 5 Example Comparative
Comparative Comparative Comparative Emulsion Used 1 Example 1
Example 2 Example 3 Example 4 Hydrostatic Resistance .gtoreq.500
.gtoreq.500 .gtoreq.500 .gtoreq.500 .gtoreq.500 (mm) Water
Repellency 80 80 80 50 80 Oxygen Index 18.2 22.4 22.3 23.2 23.6
Adherence to Fabric + + + + + Overall Evaluation as Very Unsuitable
Unsuitable Unsuitable Unsuitable due to Tent Fabric Suitable due to
due to due to Unsatisfactory Flame unsatisfactory unsatisfactory
unsatisfactory Retardancy Flame Flame Flame Retardancy Retardancy
Retardancy
Example 3
[0049] Two parts of dodecylbenzene sulfonic acid and 53.64 parts of
water were added to a mixture of 40 parts of a dimethylcyclic
siloxane with a DP of four and 4 parts of a methylvinylcyclic
siloxane with a DP of 4, and the combination was mixed to
homogeneity for 30 minutes with a stirrer. The resulting mixture
was passed twice through an homogenizer emulsifier at a pressure of
350 kg/cm.sup.2 and provided a uniform emulsion. This emulsion was
held for two hours at 85-90.degree. C. and thereafter cooled to
20-30.degree. C. and polymerized for three hours. 0.36 parts of
sodium carbonate was added for neutralization. The product was an
emulsion containing a dimethysiloxane-methylvinylsiloxane
copolymer. It is referred to hereafter as base emulsion A. The
extracted diorganopolysiloxane copolymer was a gum material with
the same average molecular formula shown in Example 1.
[0050] A pre-prepared aqueous solution of 0.25 g sodium persulfate
dissolved in 5 parts water was added to 90 parts of base emulsion
A, and the reaction system was held at 75-78.degree. C. A liquid
mixture containing 5 parts of methyl methacrylate, 11 parts of
butyl acrylate, and 15 parts of ethyl acrylate, was added dropwise
to the base emulsion A in small aliquots from an addition funnel.
Holding for three hours after completion of the addition provided
emulsion B-1. When this copolymer containing emulsion B-1 was
spontaneously dried in an aluminum cup, and then heated for 5
minutes at 130.degree. C., the result was a strong, almost
transparent coating. This confirms that dimethylsiloxane-methylvin-
ylsiloxane copolymer and the acrylic acid monomer had undergone
homogeneous copolymerization. To 85.0 parts of emulsion B-1 were
added to 15 parts of colloidal silica, 0.2 parts of diethylamine as
the pH adjusting agent, and 0.3 parts of a 50 percent emulsion of
dibutyltin dilaurate. The mixture was allowed to dissolve and then
dispersed to homogeneity. It was aged for one week at
45.+-.3.degree. C. to provide emulsion B-2. To 100 parts of
emulsion B-2 were mixed and added 8 parts of microparticulate
aluminum hydroxide and two parts of hexabromocyclododecane. This
provided a composition referred to hereafter as emulsion
composition B-3. One part of sodium polyacrylate was added to
emulsion composition B-3 to adjust its viscosity to 20,000 mPa.s,
and it was then coated with an applicator on polyester base fabric
used for automotive airbags so as to provide a film thickness of 40
.mu.m. The coated fabric was dried by allowing it to stand
overnight at room temperature, and then it was heat treated for 5
minutes at 130.degree. C. The coating on the coated airbag fabric
was tightly adhered to the surface. No tack was observed, and its
oxygen index was an 18.2. These results confirmed that emulsion
compositions according to the invention are very suitable for use
as coatings for airbags.
Example 4
[0051] Cashmere doeskin suit cloth of 100 percent polyester was
dipped for 5 seconds in a 3 weight percent dilution of emulsion A-3
prepared in Example 1, wrung out on a mangle roll at a 100 percent
expression ratio, and heated for 5 minutes at 150.degree. C. The
resulting treated fabric was evaluated for handle by tactile
manipulation. It was found to have a highly resilient and elastic
handle. These results confirm that emulsion compositions according
to the invention are well suited for application as dip treatments
for synthetic fiber fabrics and textiles. The flameproofness was
also evaluated by bringing the treated fabric into contact with the
lighted end of a cigarette. The fabric did not melt, and no holes
were produced even during contact for 30 seconds with the red
combustion region of the cigarette. In contrast, an approximately
7.5 mm hole was produced in 5 seconds due to melting when untreated
cashmere doeskin fabric was contacted with the lighted end of the
cigarette.
[0052] Diorganopolysiloxane/acrylate ester copolymer containing
emulsion compositions with components (A)-(D) possess the ability
to form flexible, highly flame retardant coatings upon curing at
room temperature through removal of the water fraction. Fabrics
treated with these emulsion compositions also possess excellent
flame retardancy.
[0053] Other variations may be made in compounds, compositions, and
methods described herein without departing from the essential
features of the invention. The embodiments of the invention
specifically illustrated herein are exemplary only and not intended
as limitations on their scope except as defined in the appended
claims.
* * * * *